Life among the frozen
The term “biological hotspot” is not one you expect to connect with Antarctica, the most remote and inhospitable continent on Earth. Antarctica remains the only continent to be surrounded by a single current, the Antarctic circumpolar current, which flows eastward and connects water from all of the other major oceans. Scientists have long studied this frigid landscape and marveled at the whales, seals and penguins that call this land and the surrounding ocean their home. Just below the surface of the ice, however, a hidden ecosystem teems with life. Microscopic, photosynthesizing “plants” called phytoplankton fill these nearshore waters, making the water below the ice look green or brown. These organisms form the base of the Antarctic food chain, and serve as food for the larger organisms up through food chain. How do these phytoplankton live below the ice where water temperature is below freezing? Sufficient light is able to pass through the ice to support photosynthesis, and the cycle of ice formation and melt produces natural turbulence that carries the essential nutrients that these phytoplankton need up to the surface. This upwelling phenomenon occurs most often in the shallow, nearshore waters, such as along the Western Antarctic Peninsula (WAP), or the “tail” of the Antarctic continent. The strong biological activity in the nearshore regions is in stark contrast to the majority of the Southern Ocean, which is largely devoid of phytoplankton. We’ll talk about why that is on the next On the Ocean! This has been On the Ocean, a program made possible by the Department of Oceanography and a production of KAMU-FM on the campus of Texas A&M University in College Station. For more information and links, please go to ocean.tamu.edu and click “On the Ocean”.
Script Author: Laramie Jensen
Krill larvae under the sea ice in Antarctica